CO-ADSORPTION AND KATE OF EXTRACTION IN A COPPER CHLORIDE SYSTEM CONTAINING DECANOL AND HYDROPHOBIC PYRIDINE ACID DERIVATIVES

The model compounds di-2-ethylhexyl pyridine-3,5-dicarboxylate and N,N,Nʹ,Nʹtetrahexyl pyridine-3,5-dicarboxamide were synthesised and their copper(II) extraction properties from chloride solutions were described. The effect of decanol used as a modifier on copper extraction was studied. The interfacial tension at the toluene/water interface was measured for systems containing the individual extractants and their mixtures with decanol. It was found that decanol affects the composition of the mixed adsorbed layer at the toluene/water interface. However, decanol significantly decreases only the rate of copper extraction with di-2-ethylhexyl pyridine-3,5-dicarboxylate. The effect disappears at high concentrations of the ester and is almost negligible for N,N,Nʹ,Nʹtetrahexylpyridine-3,5-dicarbox-amide, which shows significantly higher extraction ability in comparison to the ester.